When you import a still image in Cinemagraph Pro, it'll automatically occupy the scale of your video. If the still image is stretched or doesn't align with the motion component of your cinemagraph, your source video and still image likely have different aspect ratios.

The most common aspect ratio for video recording is 16:9. Common aspect ratios for photos include 3:2, 4:3, 16:9, and 1:1. For best results when using a photo outside of your source video, we suggest capturing both components using the same aspect ratio.

If your video and image do not have the same aspect ratio, you can crop or resize either component to match the aspect ratio of the other component. Doing so may not result in the desired effect which is why it's important to try and capture your video and photo using the same aspect ratio to begin with.

To check the dimensions of your video and photo, control+click on the files and select Get Info or use the keyboard shortcut ⌘I. You can use an online aspect ratio calculator to verify the aspect ratios of your video and photo and help you determine which component needs to be cropped or resized.

When cropping or resizing, enter the new dimensions in the video or photo editing application of your choice. If you aren't sure how to crop or resize photos and videos in the application you're using, check their Help Center for assistance.